Answer: The original volume in liters was 0.0707L
Explanation:
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,
where,
= initial pressure of gas = 0.85 atm
= final pressure of gas = 456 mm Hg = 0.60 atm (760mmHg=1atm)
= initial volume of gas = ?
= final volume of gas = 94.0 ml
= initial temperature of gas = 
= final temperature of gas = 
Now put all the given values in the above equation, we get:
(1L=1000ml)
Thus the original volume in liters was 0.0707L
<span>Ferns and reptiles appeared in the paleozoic era.</span>
Answer:
only columns
Explanation:
All atoms of elements present in same group or column having same number of valance electrons. Thus the elements in same group having same properties.
For example:
Consider the second group. It consist of alkaline earth metals. There are six elements in second group. Beryllium, magnesium, calcium, strontium, barium and radium.
All have two valance electrons.
Electronic configuration of Beryllium:
Be = [He] 2s²
Electronic configuration of magnesium.
Mg = [Ne] 3s²
Electronic configuration of calcium.
Ca = [Ar] 4s²
Electronic configuration of strontium.
Sr = [Kr] 5s²
Electronic configuration of barium.
Ba = [Xe] 6s²
Electronic configuration of radium.
Ra = [ Rn] 7s²
They are present in group two and have same number of valance electrons (two valance electrons) and show similar reactivity.
They react with oxygen and form oxide.
2Ba + O₂ → 2BaO
2Mg + O₂ → 2MgO
2Ca + O₂ → 2CaO
this oxide form hydroxide when react with water,
BaO + H₂O → Ba(OH)₂
MgO + H₂O → Mg(OH)₂
CaO + H₂O → Ca(OH)₂
With sulfur,
Mg + S → MgS
Ca + S → CaS
Ba + S → BaS
The neutralization of the base with an acid will result to the formation of salt and water. In this case, a mole of strong acid will have one halide that will react with the Na atom. Since there are two Na atoms in each of the molecule of Na2HPO4, this will need 2 halide atoms.
